Cellulose fibre

ABSTRACT

This invention relates to a process for the production of a cellulose molded body according to the amine-oxide process, which results in a molded body having reduced and effectively controllable fibrillation properties.

INTRODUCTION

The present invention is concerned with a new cellulose moulded body anda process for the production of this cellulose moulded body.Particularly, the present invention is concerned with a new cellulosefibre and a new cellulose film having a predetermined tendency tofibrillation.

BACKGROUND OF THE INVENTION

As an alternative to the viscose process, in recent years there havebeen described a number of processes wherein cellulose, without forminga derivative, is dissolved in an organic solvent, a combination of anorganic solvent and an inorganic salt, or in aqueous saline solutions.Cellulose fibres made from such solutions have received by BISFA (TheInternational Bureau for the Standardisation of man made Fibres) thegeneric name Lyocell. As Lyocell, BISFA defines a cellulose fibreobtained by a spinning process from an organic solvent. By "organicsolvent", BISFA understands a mixture of an organic chemical and water.

So far, however, only one process for the production of a cellulosefibre of the Lyocell type has achieved industrial-scale realization. Inthis process, in the following referred to as amine-oxide process, atertiary amine-oxide, particularly N-methylmorpholine-N-oxide (NMMO), isused as a solvent. Such a process is described for instance in U.S. Pat.No. 4,246,221 and provides fibres which exhibit a high tensile strength,a high wet-modulus and a high loop strength.

A typical feature of the Lyocell fibres is their pronounced tendency tofibrillate when wet. Fibrillation means the breaking up of the fibre inlongitudinal direction at mechanical stress in a wet condition, so thatthe fibre gets hairy, furry. The reason for fibrillation may be that thefibres consist of fibrils which are arranged in the longitudinaldirection of the fibre axis and that there is only little crosslinkingbetween these.

WO 92/14871 describes a process for the production of a fibre having areduced tendency to fibrillation. The reduced tendency to fibrillationis attained by providing all the baths with which the fibre is contactedbefore the first drying with a maximum pH value of 5.5.

WO 92/07124 also describes a process for the production of a fibrehaving a reduced tendency to fibrillation wherein the never dried fibreis treated with a cationic polymer. As such a polymer, a polymer havingimidazole and azetidine groups is mentioned. Additionally, there may becarried out a treatment with an emulsifiable polymer, such aspolyethylene or polyvinylacetate, or a crosslinking with glyoxal.

In a lecture given by S. Mortimer at the CELLUCON conference in 1993 inLund, Sweden, it was mentioned that the tendency to fibrillation risesas drawing is increased.

There have been published already some methods to reduce the tendency tofibrillation of Lyocell fibres:

Thus from WO 95/02082 of the applicant it is known that fibrillation maybe reduced by certain combinations of spinning parameters.

Moreover, it is known that the fibrillation properties of Lyocell fibresmay be improved by chemical crosslinking. Thus, e.g. EP-A - 0 538 977describes crosslinking of Lyocell fibres with chemical reagents able toreact with cellulose in a state before any drying, i.e. when the fibreis produced, as well as in a dried state, i.e. substantially duringfinishing of the textile fabrics.

Crosslinking Lyocell fibres during finishing has the main drawback forthe finishing operator of requiring additional steps which causeadditional costs. Also, the application of such additional steps limitsthe variety of produceable textile fabrics, which again restricts themarketing possibilities of the Lyocell fibres. Another essentialdisadvantage of the treatment of Lyocell fibres after a first dryingconsists in that the susceptibility of the fibres for crosslinkingchemicals is significantly reduced, particularly after the first drying,as compared to the state they exhibit when they are freshly spun. Thisrequires the use of greater amounts of chemicals.

The crosslinking reagents exemplified in the above patent applicationexhibit as groups capable of crosslinking halogen-substituted,nitrogen-containing ring structures able to react with the hydroxylgroups of the cellulose in alkaline conditions. Moreover, compoundscomprising vinyl sulphone groups or their precursors are described.These compounds substantially also react only when alkali is added, orthey require alkali as a neutralisation reagent for split off acids. Theprocedures proposed in this patent application for crosslinking neverdried Lyocell fibres have serious drawbacks insofar as it is difficultand requires a complex arrangement to carry them out in a continuousfibre post-treatment process. When very reactive compounds of thesuggested compound classes are used, a separate application of thecrosslinking substances from the basic compounds necessary to initiatethe reaction with the cellulose is required. When less reactivecompounds are used, frequently a simultaneous application of thecrosslinking agents and the alkali is possible, but in this case atemperature step has to be carried out which in the indicated patentapplication is attained by "steaming". Thus, a serious drawback of theindicated patent is an increase of the number of post-treatment steps,which implies a significant cost raise, especially when constructing aplant for the production of such a fibre.

However, there is still another drawback to this procedure. Whenhalogenated, nitrogen-containing rings or the vinyl sulphones and theirprecursor substances respectively are reacted, salts are formed duringthe crosslinking reaction which have to be washed out of the fibreafterwards. Moreover, also excess residual chemicals not reacted withthe cellulose have to be washed out. This means that in a continuousfibre production process, another post-treatment step is necessary,causing further investment and operating costs and creating additionalproblems with contaminated waste water.

In WO 94/24343 of the applicant, similar processes for crosslinkingLyocell fibres to reduce fibrillation are proposed, describing the useof alkali buffers and an exposure to electromagnetical waves asparticularly advantageous.

WO 94/20656 describes a reduction of the fibrillation of Lyocell fibresby means of crosslinking using conventional crosslinking chemicalsusually employed to improve crease angles of cellulose textiles while asimultaneous reduction of the dye absorption is prevented when thecrosslinking is carried out in the simultaneous presence of flexible,linear polymers. Substantially, conventional N-methylol resins(containing a low formaldehyde level) and the usual acidic catalysts areused. This method is described as efficient for use on the dried as wellas on the never dried fibre.

But also this procedure has drawbacks which make another crosslinkingmethod desirable. The methylol resins usually employed for improving thewet crease angles need relatively high reaction temperatures, generallyfrom 120° C. to 160° C., to react with the OH groups of the cellulose,when the reaction is to be carried out at a sufficient rate. In theinternational patent application indicated, also very high temperaturesfor fixing the crosslinking agents are applied. This implies always amore or less significant loss of fibre strength, but above all a loss offibre elongation and loop strength, and the fibre is getting brittle.Moreover, in the cited patent application no comparative physical fibreparameters before and after the crosslinking reaction are indicated.Reactions with the cited N-methylol compounds at low temperatures andthus a higher fibre moisture, which do not imply such serious strengthand elongation losses, usually require very long reaction times andtherefore are hardly suitable for continues fibre production processes.

Moreover it is known that cellulose fibre textiles may be dyed withconventional reactive dyes at neutral pH values without adding salt whenthey are appropriately pre-treated (Lewis et al., JSDC volume 107, March1991, and JSDC volume 109, November 1993). The nitrogen hetero ringscontaining vinyl sulphone or halogens which under alkaline conditionsusually react as anchoring groups with the hydroxy groups of thecellulose will react with the amino groups without addition of alkali,since they represent significantly stronger nucleophiles than thehydroxy groups.

In "Chemical Aftertreatment of Textiles" (H. Mark, N. S. Wooding, S. M.Atlas), page 414, a wet crosslinking of quaternizeddiethylaminocellulose in hydroxy form at room temperature is described.

In the Italian patent application 690,926 (1965), the inner salt oftrissulfatoethylsulphonium for the alkaline crosslinking of gelatine isdescribed. The reaction is carried out at pH 7 and at a temperature of50° C.

BRIEF SUMMARY OF THE INVENTION

It is the objective of the invention to produce a Lyocell moulded bodyhaving reduced and effectively controllable fibrillation properties bymeans of crosslinking reactions, while the production process does nothave the disadvantages described of the known crosslinking processes. Itis another objective of the invention to provide fibres having improvedwet crease angles in a textile fabric, thus allowing the production ofLyocell textiles without any of the high-grade finishing chemicalsusually employed in textile finishing.

According to the invention, this objective is attained by means of aprocess according to the amine-oxide process for the production of acellulose moulded body, wherein a suspension of cellulose in an aqueoustertiary amine-oxide is transformed into a spinnable solution, extrudedthrough a spinneret, and the moulded body obtained is conducted througha precipitation bath, which process is characterized in that

(a) a suspension containing a substance able to react with the celluloseand to incorporate functional groups which are more nucleophilic thanthe hydroxy groups of the cellulose is employed; and/or

(b) a cellulose carrying functional groups which are more nucleophilicthan the hydroxy groups of the cellulose is employed, and/or

(c) a suspension containing a polymer carrying functional groups whichare more nucleophilic than the hydroxy groups of the cellulose isemployed, and/or

(d) a substance capable of reacting with the cellulose and incorporatingfunctional groups which are more nucleophilic than the hydroxy groups ofthe cellulose is added to the spinnable solution; and/or

(e) a polymer carrying functional groups which are more nucleophilicthan the hydroxy groups of the cellulose is added to the spinnablesolution.

According to the invention, the object is also attained by means of aprocess for the production of a cellulose moulded body according to theamine-oxide process, wherein a suspension of cellulose in an aqueoustertiary amine-oxide is transformed into a spinnable solution, extrudedthrough a spinneret and the moulded body obtained is conducted through aprecipitation bath, which process is characterized in that

(a) functional groups which are more nucleophilic than the hydroxygroups of the cellulose are incorporated into the moulded body obtained,or

(b) the moulded body obtained is contacted with an oligomer or a polymercarrying functional groups which are more nucleophilic than the hydroxygroups of the cellulose, whereafter

the moulded body is treated with a crosslinking agent which reacts withthe nucleophilic groups, provided that it substantially does not reactwith the hydroxy groups of the cellulose.

DETAILED DESCRIPTION OF THE INVENTION

For the purposes of the present specification and claims, the term"moulded body" denotes particularly fibres and films. In the following,the term "fibres" denotes fibres, films and also other moulded bodies.

To obtain the known good physical fibre parameters such as a high wetstrength, a high loop strength and a high wet-modulus, according to theinvention the fibre is preferably crosslinked in humid state. Moisturecontents of 40% up to a free swelling which occurs when the fibre floatsin a long bath are preferred.

In a particularly preferred embodiment, the fibre has a moisture contentof between 70% and 150% during the crosslinking reaction. Thecrosslinking is achieved by incorporating into the fibre groups whichare more nucleophilic than the hydroxy groups of the cellulose fibrealready before treatment with the crosslinking agent, which groups reactwith the crosslinking agent without addition of further alkali. Thecrosslinking agents are generally known chemicals used in the textilefinish of cellulose textiles. Substantially, they are molecules carryingthe known reactive groups of the reactive dyes, which may be coloured ornot coloured.

Obviously, those skilled in the art may employ also others than thecrosslinking chemicals here indicated, such as commercially availablecrosslinking chemicals as well as new ones specifically synthesized forthe crosslinking of Lyocell fibres. The compounds may contain at leasttwo reactive groups identical or different from each other whereupon thenucleophilic groups may act, and they also may comprise several suchgroups. Reactive polymers having a variety of nucleophilic groups arealso possible.

The reactive groups are preferably vinyl sulphone groups or theirprecursor structures or halogenated nitrogen hetero rings, particularlytriazine rings having one or two halogen atoms, and also epoxy groups.The nucleophilic groups incorporated into the cellulose fibre beforecrosslinking are preferably primary or secondary amino groups whichreact very easily, usually already at room temperature, with thecrosslinking reagents indicated, but also other nucleophilic groupsknown to those skilled in the art such as thiol groups have the sameeffect. In the crosslinking reactions according to the invention, thereaction does not take place between the crosslinking agent moleculesand the hydroxy groups of the cellulose, but between the crosslinkingagent molecules and the more nucleophilic groups.

Thus there are several possibilities to incorporate the nucleophilicgroups capable of crosslinking according to the invention:

a) State of the art of the amine-oxide process is the production of thecellulose solution producing a two-phase mixture of pulp and aqueousNMMO in a concentration and at a temperature whereat the cellulose willnot yet dissolve, and subsequently the removal of the excess water at anelevated temperature in a vacuum and under a strong shearing of themixture, forcing the dissolution of the cellulose when a concentrationsubstantially corresponding to the NMMO monohydrate is reached. Toincorporate the nucleophilic groups it is possible to add cellulosereactive substances to the two-phase cellulose/NMMO mixture which reactunder alkaline conditions. A preferred embodiment is the addition atthis point of primary and secondary epoxy compounds containing aminogroups which during the production of the solution react with thecellulose to cellulose containing amino groups. This reaction may beadditionally catalyzed by means of small amounts of alkali.

Obviously, those skilled in the art may carry out at this point alsoother alkaline substitution reactions on the cellulose which lead tonucleophilic reaction centres in the cellulose. Thus, instead of theepoxy compounds, e.g. also the appropriate epichlorohydrines andsuitably higher amounts of alkali may be employed. This procedurehowever implies a higher purification effort when recovering thesolvent, due to the formation of salt during the reaction. Moreover, theaddition of compounds having an activated double bond containingadditionally amino groups is possible. Even the addition of aminogroup-containing (secondary and primary) cellulose reactive polymers atthis point is effective.

b) When producing the solution according to the invention, instead of aderivatisation of the pulp employed also polymers having morenucleophilic groups than the cellulose may be added, which polymers areprecipitated simultaneously with the cellulose when precipitating thecellulose solution in the spinning bath and incorporated into thecellulose filaments. Examples for such substances include chitosans,amino-group containing starch derivatives, amino-group containingcellulose derivatives as well as natural proteins such as gelatine andthe like.

When selecting these amino-group containing polymers, those skilled inthe art will take care that the polymers dissolve well or at leastdistribute well in the NMMO/cellulose solution and that in the spinningbath they are incorporated to a great extent in the freshly precipitatedfibre, since otherwise also in this case increased efforts forrecovering the solvent and purifying have to be undertaken. Thus, hardlysoluble polymers and/or polymers having a high substantivity tocellulose, such as polymers carrying quaternary groups additionally tothe reactive amino groups, are particularly suitable.

c) The amino groups (or other more nucleophilic groups than the hydroxygroups of the cellulose) may be incorporated into the never dried fibrealso in the fibre post-treatment after removing the NMMO attached afterfibre regeneration. E.g., the fibre may be treated in a never driedstate with an acidic solution of chitosans which is rendered insolublein and on the fibre by a subsequent treatment with water whereto a basehas been added. Then the fibres modified with nucleophilic groups thusobtained may be reacted with the crosslinking chemicals according to theinvention.

Another way of applying polymers containing nucleophilic groups in fibrepost-treatment is concerned with the use of polymers and oligomershaving a high substantivity to cellulose. Such polymer molecules carryadditionally to the nucleophilic groups cation groups to increase theirsubstantivity. Also the never dried cellulose fibres thus obtainedcontaining reactive, nucleophilic groups may then be reacted accordingto the invention with the described crosslinking molecules.

By incorporating a precisely defined amount of groups being morenucleophilic than the hydroxy groups of the cellulose, new cellulosefibres having an effectively adjustable crosslinking degree may beproduced. The crosslinking degree determines the tendency tofibrillation such that a high crosslinking degree results in a fibrehaving a reduced tendency to fibrillation and inversely a lowcrosslinking degree results in a fibre having a high tendency tofibrillation. Thus the present invention is also concerned withcrosslinked cellulose fibres exhibiting a predetermined tendency tofibrillation which may be produced from the new, not crosslinkedcellulose fibres.

The crosslinking of the cellulose fibres may also be carried out afterdrying the not crosslinked cellulose fibres.

The invention will now be described in more detail by means of thefollowing examples.

EXAMPLE 1

Polyacrylamide (2% by mass, based on cellulose; produced by SigmaAldrich) having a molecular mass of 5,000,000-6,000,000 g/mol wasdissolved under stirring in a 50% NMMO solution.

The amount of pulp adequate to the NMMO/water/polyacrylamide portionsfor producing a spinning solution having a cellulose content of 15% bymass was mixed with the NMMO/water/polyacrylamide solution in a kneadingdevice. The spinning solution was produced under heating andvolatilization of water at reduced pressure.

The resulting spinning solution was spun in a spinning device (spinningtemperature: 115° C.; hole diameter: 100 μm; air gap (distance betweennozzle and spinning bath): 3 cm; climate in the air gap: 30 g H₂ O/kgair) to produce a filament (titer: 1.7 dtex). This filament served as anassay material in crosslinking operations.

The nitrogen content of the fibre material thus obtained was 0.21 g/kgfibre. Of this fibre, the abrasion value was determined (see below).Furthermore, it was treated with a crosslinking solution (see below).The abrasion value of the crosslinked fibre was also determined.

Crosslinking

The fibre was dried and for a period of 10 minutes was impregnated witha glyoxal solution (concentration 5 g/l; pH 7) at room temperature andwas squeezed out to a residual moisture content of 120%. Subsequently itwas heated for a period of 10 minutes at 100° C., then washed and driedat 60° C.

Determination of the abrasion value

In order to determine the abrasion value, the fibre was laid over arotatable shaft covered with a wet viscose fabric. Here the fibre wasclamped fast at an angle of 50° relative to the axis of rotation of theshaft and was loaded with a pretension weight of 70 mg at the lower end.

The shaft was rotated at a speed of 500 r.p.m., and the time tillbreaking of the thread was measured. This was the base to calculate thenumber of revolutions necessary for wearing through, i.e. abrading. Thecrosslinking strength can thus be inferred from the number ofrevolutions, the crosslinking naturally being stronger the greater thenumber of revolutions necessary for wearing through the thread.

To determine the abrasion value, 20 samples of filaments were examinedeach time and the mean value was determined, which subsequently wasdivided by the titer of the examined fibre. Hence the dimension of theabrasion value is revolutions/dtex.

Table 1 below lists the results of the following three fibres:

Fibre (1), a pure cellulose fibre (Lyocell fibre), produced withoutaddition of polyacrylamide but crosslinked with glyoxal;

Fibre (2), a cellulose/polyacrylamide fibre, not crosslinked withglyoxal;

Fibre (3), a cellulose/polyacrylamide fibre, crosslinked with glyoxal.

                  TABLE 1                                                         ______________________________________                                        Fibre                  Abrasion value                                         ______________________________________                                        (1) cellulose fibre (without polyacrylamide;                                                         59                                                     crosslinked)                                                                  (2) cellulose/polyacrylamide fibre                                                                   49                                                     (not crosslinked)                                                             (3) cellulose/polyacrylamide fibre                                                                   198                                                    (crosslinked)                                                                 ______________________________________                                    

From Table 1 it can be seen that fibre (3) exhibits the highest abrasionvalue and that the addition of polyacrylamide provided in accordancewith the invention increases the abrasion value from 59 to almost 200.

EXAMPLE 2

The procedure here was analogous to that used in Example 1, with theproviso that the spinning solution was produced without polyacrylamideand that, prior to spinning, 1.5% polyethylene imine ("Lugalvan" G35,manufacturer: BASF; MW: 2000) was introduced into the spinning solution.

Crosslinking was also carried out analogous to Example 1, but by meansof trifunctional epoxide (1% solution of 1,3,5-triglycidyl isocyanurate;trademark: Araldit; manufacturer: Ciba Geigy).

The results of the abrasion test (cf. Example 1) are given in Table 2below.

                  TABLE 2                                                         ______________________________________                                        Fibre               Abrasion value                                            ______________________________________                                        (4) cellulose/polyethylene imine fibre                                                            13.4                                                      (not crosslinked)                                                             (5) cellulose/polyethylene imine fibre                                                            41.0                                                      (crosslinked)                                                                 ______________________________________                                    

EXAMPLE 3

A 50% aqueous solution of polyethylene imine was added to a spinningsolution having a cellulose content of 12% by mass, and said spinningsolution was then spun according to Example 1 to obtain fibres. Theresulting fibre exhibited a nitrogen content of 1.05% and for a periodof 2 minutes was impregnated with a solution containing2.4-dichlor-6-aminobenzene-4'-sulfatoethylsulphone-s-triazine (10 g/l)and soda (20 g/l), was squeezed out to a residual moisture content of130% and heated in the drying chamber for a period of 10 minutes at 120°C.

This fibre modified with polyethylene imine exhibited an enhancedreactivity to the crosslinking agent used here and also to other,similar crosslinking agents.

The abrasion values were determined as described in Example 1 and arelisted in Table 3 below.

                  TABLE 3                                                         ______________________________________                                        Fibre               Abrasion value                                            ______________________________________                                        (6) cellulose/polyethylene imine fibre                                                            24.1                                                      (not crosslinked)                                                             (7) cellulose/polyethylene imine fibre                                                            100                                                       (crosslinked)                                                                 ______________________________________                                    

EXAMPLE 4

A cellulose fibre (Lyocell fibre) was impregnated with a 0.5% aceticchitosan solution (pH 5) for a period of 10 minutes at 40° C. and wassqueezed out to a residual moisture content of 130%, was subsequentlyheated in the drying chamber for a period of 5 minutes at 100° C. andfinally rinsed.

The fibre thus modified with chitosan was impregnated with a solutioncontaining2,4-dichloro-6-aminobenzene-4'-sulfatoethylsulphone-s-triazine (10 g/l)and soda (20 g/l) for a period of 2 minutes, was squeezed out to aresidual moisture content of 130% and heated in the drying chamber for aperiod of 10 minutes at 120° C.

This fibre modified with chitosan exhibited an enhanced reactivity tothe crosslinking agent used here and also to other, similar crosslinkingagents.

The abrasion values were determined as described in Example 1 and arelisted in Table 4 below.

                  TABLE 4                                                         ______________________________________                                        Fibre              Abrasion value                                             ______________________________________                                        (8) cellulose fibre (crosslinked)                                                                366                                                        (9) cellulose/chitosan fibre                                                                     1276                                                       (crosslinked)                                                                 ______________________________________                                    

EXAMPLE 5

A dried cellulose fibre (Lyocell fibre) was impregnated with a solutioncontaining N-hydroxymethylacrylamide (110 g/l) and zinc chloride (10g/l) for one minute at room temperature, was subsequently squeezed outto a residual moisture content of 130%, then pre-dried for one hour at60° C. and set at 150° C. The nitrogen content of the fibre was 0.38% bymass.

The fibre modified with N-hydroxymethylacrylamide was boiled with a 25%ammonia solution for one hour, whereby a fibre with additionalfunctional groups was obtained (0.96% N). This fibre was crosslinkedwith a solution containing2,4-dichloro-6-aminobenzene-4'-sulfatoethylsulphone-s-triazine (10 g/l)but no alkali in accordance with Example 3.

This fibre modified with N-hydroxymethylacrylamide exhibited an enhancedreactivity to the crosslinking agent used here and also to other,similar crosslinking agents.

The abrasion values were determined as described in Example 1 and arelisted in Table 5 below.

                  TABLE 5                                                         ______________________________________                                        Fibre                   Abrasion value                                        ______________________________________                                        (10) cellulose fibre (crosslinked without alkali)                                                     50                                                    (11) cellulose fibre containing amino groups                                                          6952                                                  (not crosslinked)                                                             (12) cellulose fibre containing amino groups                                                          10306                                                 (crosslinked)                                                                 ______________________________________                                    

EXAMPLE 6

In a kneading machine (HKD-T by IKA-Labortechnik) a spinning solutionwas produced from 20 g pulp, 308 g aqueous NMMO (50%) and 1 g gelatinunder volatilization of the excess amount of water.

A melt index device by Davenport, which is common in plasticsprocessing, was used as the spinning device. The device in questionconsists of a heated, temperature-controlled cylinder into which thespinning solution was filled. By means of a piston the spinning solutionwas extruded through the spinneret (hole diameter: 100 μm) arranged onthe lower surface of the cylinder(spinning solution: 100° C.; output:0.025 g/hole/min). The selected air gap was 40 mm. The fibre obtainedwas washed with water and was crosslinked directly afterwards, that is,in the never dried state.

For crosslinking, 1 g fibre in the form of a strand was impregnated atroom temperature in 100 ml of an aqueous solution of the inner salt ofdisodium-tris(β-sulfatoethyl)sulphonium (2.7 g/l; pH 8) for a period of5 minutes and was subsequently squeezed out to a residual moisturecontent of 140%. After this the fibre was dried overnight at 60° C.

The resulting fibre was examined for its tendency to fibrillate by meansof the shaking test described below:

8 fibres having a length of 20 mm were placed in a 20 ml sample bottletogether with 4 ml water and for a period of 9 hours were shaken on alaboratory shaking device, type RO-10 by Gerhardt of Bonn, (DE), atspeed 12. Subsequently, fibrillation of the fibres was judged under themicroscope by counting the fibrils formed on 0.276 mm of fibre length.With this test, a Lyocell type cellulose fibre formed 50 fibrils. Amodal type cellulose fibre known as having a low fibrillation rate, withthis test exhibited 1 to 2 fibrils.

Table 6 below gives the result of the shaking test of the fibre inaccordance with Example 6 (fibre 14) as well as of a cellulose fibrethat has not been crosslinked, for comparison.

EXAMPLE 7

The procedure here was analogous to that used in Example 6, except thatinstead of gelatin, 0.6 g polyvinyl amine were added to the spinningsolution. For producing the polyvinyl amine, polyvinyl aminehydrochloride (manufacturer: Hoechst) was neutralized and freeze dried.

Spinning and crosslinking as well as the test for fibrillation werecarried out analogous to Example 6. The result can be seen from table 6below.

                  TABLE 6                                                         ______________________________________                                        Fibre                 Number of fibrils                                       ______________________________________                                        (13) cellulose fibre (not crosslinked)                                                              >50                                                     (14) cellulose fibre modified with gelatin                                                          30                                                      (crosslinked)                                                                 (15) cellulose fibre modified with                                                                  40                                                      polyvinyl amine (crosslinked)                                                 ______________________________________                                    

We claim:
 1. A process for the production of a cellulose molded bodyaccording to an amine-oxide process comprising the steps of(a) providinga suspension of cellulose in an aqueous tertiary amine-oxide, thesuspension including a substance which reacts with the cellulose andincorporates functional groups therein which are more nucleophilic thanhydroxyl groups in the cellulose; (b) transforming the suspension ofcellulose into a spinnable solution; (c) extruding said solution througha spinneret thereby forming a molded body; and (d) conveying the moldedbody to a precipitation bath.
 2. A process for the production of acellulose molded body according to an amine-oxide process comprising thesteps of(a) providing a suspension of cellulose in an aqueous tertiaryamine-oxide wherein the cellulose comprises functional groups which aremore nucleophilic than hydroxy groups of said cellulose; (b)transforming the suspension of cellulose into a spinnable solution; (c)extruding said solution through a spinneret thereby forming a moldedbody; and (d) conveying the molded body to a precipitation bath.
 3. Aprocess for the production of a cellulose molded body according to anamine-oxide process comprising the steps of(a) providing a suspension ofcellulose in an aqueous tertiary amine-oxide, the suspension including apolymer having functional groups which are more nucleophilic thanhydroxyl groups of said cellulose; (b) transforming the suspension ofcellulose into a spinnable solution; (c) extruding said solution througha spinneret thereby forming a molded body; (d) conveying the molded bodyto a precipitation bath.
 4. A process for the production of a cellulosemolded body according to an amine-oxide process comprising the stepsof(a) providing a suspension of cellulose in an aqueous tertiaryamine-oxide; (b) transforming the suspension of cellulose in an aqueoustertiary amine-oxide into a spinnable solution; (c) adding a substanceto the spinnable solution which reacts with the cellulose andincorporates functional groups therein which are more nucleophilic thanhydroxy groups of the cellulose; (d) extruding said solution through aspinneret thereby forming a molded body; and (e) conveying the moldedbody to a precipitation bath.
 5. A process for the production of acellulose molded body according to an amine-oxide process comprising thesteps of(a) producing a suspension of cellulose in an aqueous tertiaryamine-oxide; (b) transforming the suspension of cellulose into aspinnable solution; (c) adding a polymer to the spinnable solution, thepolymer having functional groups which arc more nucleophilic thanhydroxy groups of the cellulose; (d) extruding said solution through aspinneret thereby forming a molded body; and (e) conveying the moldedbody to a precipitation bath.
 6. A process for the production of acellulose molded body according to an amine-oxide process, comprisingthe steps of(a) providing a suspension of cellulose in an aqueoustertiary amine-oxide; (b) transforming a suspension of cellulose in anaqueous tertiary amine-oxide into a spinnable solution; (c) extrudingsaid solution through a spinneret thereby forming a molded body; (d)incorporating functional groups which arc more nucleophilic than hydroxygroups of the cellulose into the molded body; and (e) conveying themolded body to precipitation bath.
 7. A process for the production of acellulose molded body according to an amine-oxide process comprising thesteps of(a) providing a suspension of cellulose in an aqueous tearyamine-oxide; (b) transforming a suspension of cellulose in an aqueoustertiary amine-oxide into a spinnable solution; (c) extruding saidsolution through a spinneret thereby forming a molded body; (d)contacting the molded body with an oligomer or a polymer havingfunctional groups which are more nucleophilic than hydroxy groups of thecellulose; and (e) conveying the molded body to a precipitation bath. 8.A process according to any one of claims 1, 2, or 4 further comprisingthe step of contacting a crosslinking agent with the functional groupswhich are more nucleophilic than hydroxy groups of the cellulose afterthe functional groups have been incorporated into the cellulose.
 9. Aprocess according to claim 6 further comprising the step of contacting acrosslinking agent with the functional groups after the functionalgroups have been incorporated into the molded body.
 10. A processaccording to claim 7 further comprising the step of contacting themolded body with a crosslinking agent after contacting the molded bodywith an oligomer or polymer, wherein the crosslinking agent reacts withthe functional groups.
 11. A process according to claim 8 wherein thecrosslinking agent does not substantially react with hydroxy groups ofthe cellulose.
 12. A process according to claim 9 wherein thecrosslinking agent docs not substantially react with hydroxy groups ofthe cellulose.
 13. A process according to claim 9 wherein thecrosslinking agent does not substantially react with the hydroxy groupsof the cellulose.
 14. A process according to any of one of claim 1, 2,3, 4, 5, 6, or 7 wherein the functional groups include functional groupsselected from the group consisting of primary amino groups, secondaryamino groups, or thiol groups.
 15. A process according to claim 8wherein the crosslinking agent comprises at least two halogen-containingnitrogen hetero rings.
 16. A process according to claim 9 wherein thecrosslinking agent comprises at least two halogen-containing nitrogenhetero rings.
 17. A process according to claim 10 wherein thecrosslinking agent comprises at least two halogen-containing nitrogenhetero rings.
 18. A process according to claim 8 wherein thecrosslinking agent comprises at least two epoxy groups.
 19. A processaccording to claim 9 wherein the crosslinking agent comprises at leasttwo epoxy groups.
 20. A process according to claim 10 wherein thecrosslinking agent comprises at least two epoxy groups.
 21. A processaccording to claim 8 wherein the crosslinking agent comprises at leasttwo groups selected from the group consisting of vinyl sulphone groups,halogen-containing nitrogen hetero rings, and epoxy groups.
 22. Aprocess according to claim 9 wherein the crosslinking agent comprises atleast two groups selected from the group consisting of vinyl sulphonegroups, halogen-containing nitrogen hetero rings, and epoxy groups. 23.A process according to claim 10 wherein the crosslinking agent comprisesat least two groups selected from the group consisting of vinyl sulphonegroups, halogen-containing nitrogen hetero rings, and epoxy groups. 24.A process according to any one of claim 5 or 7, wherein the polymer isselected from the group consisting of chitosans, amino-group containingstarch derivatives, amino group containing cellulose derivatives, andgelatin.
 25. A cellulose molded body prepared by a process according toany one of claim 1, 2, 3, 4, 5, 6, or
 7. 26. A cellulose molded bodyprepared by the process in any one of claims 1, 2, 3, 4, 5, 6, or 7,wherein the cellulose molded body is dried.
 27. A cellulose molded bodyprepared by a process according to claim 25, wherein the cellulosemolded body is in the shape of a fiber.
 28. A cellulose molded bodyaccording to claim 25, wherein the cellulose molded is in the shape of afilm.